Crane with turntable locking means



Un1ted States Patent 1111 3,545,628

[72] Inventor Max 1. Dechantsrelter [56] References Cited A l N gg a gm UNITED STATES PATENTS [211 1 1,110,739 9/1914 Beutel 212/116 [221 FM d 323 1,210,288 12/1916 Farr 104/47 [451 1 1,442,148 1/1923 l-lilpert.. 104/47 [731 3 173 313. 3 1965 T 1 1 74 817 wmMu k w y 1 ay 0 o a: :fw m 3,420,389 1/1969 Gustetic 2l4/l6.4

' Q FOREIGN PATENTS 1,158,546 12/1963 Germany 104/47 Primary Examiner-Harvey C. Hornsby Attorney-James E. Nilles [54] CRANE WITH TURNTABLE LOCKING MEANS 7 chin" 5 Drama ABSTRACT: A crane having a rotatable turntable and locking [52] 11.5. 212/124, means for accurately positioning and releasably locking the 74/817, 104/ 48 turntable in any one of a number of predetermined positions [51] Int. Cl B66c 19/00 relative to the rest of the crane. The locking means includes [50] Field of Search 212/21, 24, means for cushioning the shock load on the locking pin due to 124, 125,39, 68, 69, ll6;214/l6.4; 104/47, 48; momentum of the rotating turntable, and also for insuring alinement of the interengaging, releasably locking parts.

PATENTEDBEB 8197B K 3545628 SHEET 1 UF 2 irmxwiy PATENTEDBEB 8|97G 3.545528 SHEET 2 UF 2 CRANE WITH TURNTABLE LOCKING MEAN BACKGROUND OF THE INVENTION The present invention pertains to traversing hoists or travelling cranes of the type having a turntable that rotates relative to the rest of the machine. This turntable has a mast or other load carrying parts attached to it for rotation therewith. These cranes and their loads are often moved in restricted areas, such as down the aisles of warehouses, and the load carried by the crane must be alined properly on the crane to prevent collision with other supplies or structures in the area. The present invention provides means for accurately locating and locking the turntable'and its loadin a certain predetermined position in respect to the rest of the crane.

Examples of some of the general types of cranes with which the present invention is used are shown in my U.S. Pat. No. 3,352,432 of Nov. 14, 1967, entitled Crane with Cable Carrier Apparatus; U.S. Pat. No. 3,250,399 of May 10, 1965, entitled Stacker Crane; U.S. lat. No. 3,286,853 of Nov. 22, 1966, entitled Stacker Crane Power Lift Mechanism and U.S. Pat. No. 3,270,893 of Sept. 6, 1966, entitled Stacker Crane Weighing Mechanism. These cranes are of the type having a downwardly depending mast from which a laterally extending load supporting fork protrudes, the mast and fork being rotatable about a vertical axis together with the turntable. It is important for the operator to be able to know exactly where the load extends laterally from the crane proper, and to be able to position and releasably lock the turntable and its load in a proper position.

SUMMARY The present invention relates to a traveling crane having a rotatable turntable from which a load supporting mast or other structure extends. More specifically the invention provides a releasable locking means for accurately positioning and releasably locking the turntable-in a predetermined position relativeto the rest of the crane. A more specific aspect of the invention relates to such a locking means having ashiftable pin on one part of the crane and which can releasably engage another relatively moving part of the crane; the pin has mounting means which cushions the shock loads due to the momentum of the moving turntable, and also permits pivoting or swiveling of the pin to insure its alinement with its interengaging part and to also accommodate the momentum of the turntable.

BRIEF DESCRIPTION'OF THE DRAWINGS FIG. 1 is an elevational view of a stacker crane embodying the present invention, certain parts being removed for clarity;

FIG. 2 is a view of the locking means shown in FIG. I, but on an enlarged scale, and certain parts being shown in section or broken away for clarity in the drawing;

FIG. 3 is a top view of the stacker crane, certain parts being removed for the sake of clarity;

FIG. 4 is an enlarged view of the locking pin and its mounting as shown in FIG. 2; and

FIG. 5 is an enlarged view of the electric cylinder as shown in FIG. 2.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring in greater detail to the drawings, the invention has been shown as applied to a stacker crane which is mounted on a pair of overhead rails 1 and 2. These rails may be suitably mounted in any conventional manner, as for example, as part of other overhead bridge structure (not shown) or as part of a building structure (not shown).

The trolley T has a series of wheels 3 which ride along and are guided by the rails 1 and 2, the wheels being suitably journaled in two parallel frame members 4 and 5. A large rectangular steel ring plate 6 is welded across the upper sides of members 45 and 5 so as to form a'rigid trolley frame. The trolley is driven along the rails in either direction by an electric motor 9 through the drive shaft 9!) on which some of the wheels 3 are fixed.

A turntable 10 is carried on the trolley for rotation about a central, vertically disposed axis, and this turntable carries a downwardly depending mast assembly MA which rotates together with the turntable as a unit about the vertical axis.

The turntable includes a large, horizontally disposed circular steel plate Ill which is rotatably supported by a large, antifriction bearing ring assembly 12 that is located on top of the plate 6. Assembly 12 includes an inner race 13 secured to the underside of the turntable, an outer race 14 secured to the upper side of the plate 6, and a series of balls 15 located between the races in the conventional manner to thus carry the vertical and horizontal thrust components.

Located on top of the turntable is the conventional electric motor 16 connected by the drive reduction unit 37 to the cable drum 18, and a brake 19 is located between the motor and drum. Other forms of electrical power equipment or hoisting devices may be providedon the turntable as the need requires, but it is believed sufficient to say for the purposes of this invention that this hoisting equipment may include cables 21 and sheaves 22 which raise and lower the telescoping mast assembly, all as taught in my-said U.S. Pat. No. 3,250,399.

An operators cab 0C is provided alongside the mast as sembly and is rigidly fixed to the mast. This operator's cab contains the controllers (not shown) for operating the electrical control apparatus located on the stationary member of the crane.

The means for supporting the electrical cables for conduct ing electrical power from the trolley portion of the crane to the rotating turntable is shown and described in my said U.S. Pat. No. 3,352,432. In any event, the operator in the cab can control all functions of the crane, including the locking means to be described hereinafter.

It will be noted that the load carrying fork structure FS is of elongated construction and it is adapted to carrying long members, such as structural steel not shown). Four forks 26, 27, 28 and 29 are provided to support the load (not shown). When working in crowded areas, such as the aisles of warehouses, the rotated position of the turntable must be accurately controlled by the operator in the cab.

The releasably locking means LM of the present invention is shown in detail in FIG. 2 and is located between the ring plate 6 of the nonrotating trolley part of the crane and the rotatable turntable plate 11. More specifically, a shiftable pin 30 is reciprocable in a sleeve 31 which in turn is swivelly mounted by its spherical ring 32. in another mounting sleeve 33. Sleeve 33 is rigidly fixed by a bracket 34 to the ring plate 6. The spherical ring is located at the lower end of the sleeves 31 and 33, and a collar of flexible or resilient material 35, is provided between the upper ends of sleeves 3i and 33. With this construction, the pin and its sleeve 31 can swivel within limits, about the spherical ring 32 and in doing so the flexible material is momentarily compressed.

The flexible material 35 may be of various types, but a polyester of a durometer hardness of about 40 to 50 has proved very satisfactory.

The pin 30 has a hole 40 extending partially along its axis, and a concentric counterbore ill. A plunger 42 is reciprocal in the hole 40 and has a collar 43 fixed thereto. A spring 44 acts between collar 43 and a shoulder 45 formed by the counterbore 41, and the spring serves to urge the pin 34'! upwardly and out of its sleeve 31. A stop collar 46 is fixed to the lower end of pin 30 and limits the outward movement of the pin in its sleeve.

The plunger is reciprocated by an electric cylinder 50 which is mounted on the trolley by the trolley girt 52. The cylinder is of the known type, having a reversing squirrel cage motor 59a built into a tubular housing, and converts the rotary motion to a linear or push puli motion by means of a screw. The motor shaft is a hollow tube 5% with an inner thread, supported in bearings located in the end, caps. Thrust limit switch assemblies Silt mounted in each end of the housing, locate the hol low shaft in the midposition, by means of thrust bearings. The push-pull rod or plunger 42' is threaded to engage the threads in the hollow shaft and is prevented from rotating by a guide key 50d in the end cap. Therefore, the turning of the rotor causes the push-pull rod to extend or retract, depending upon the direction of rotation of the motor.

At the end of the stroke, or in the event of an overload condition between stroke limits, the push-pull rod becomes stationary. The rotor continues to turn, screwing the hollow shaft back along the stationary push-pull rod approximately oneeighth of an inch, thus tripping the limit switch and disconnecting the power to the motor. It is therefore virtually impossible to damage the motor due to abnormal overload conditions, yet the thrust is maintained even though the power supply has been switched off.

Thus the cylinder 50 is actuated by the operator in the known manner to cause the plunger to extend outwardly, thus compressing the spring 44 and consequently urging the pin 30 in an outward direction.

The turntable plate 11 has an aperture 60 formed therein, and any number of these apertures may be located around the plate 11 at predetermined locations corresponding to the positions in which it is desired to move the turntable. As indicated in FIG. 3, four such positions are shown, providing four lockable positions for the turntable. The apertures 60 are defined by the hardened steel bushings 61 rigidly fixed in the steel plate 11. The apertures are tapered to readily facilitate entry of the complementary shaped end 30a of the pin 30. A shoulder 3012 on the pin bears against the hardened steel bushing 61 when the spring 44 has driven the pin 30 fully home in the bushing, thereby locking the turntable relative to the trolley.

In operation, as the turntable approaches the position in which the operator desires to lock it in place, he slows down the rotative movement of the turntable and actuates the electric cylinder 50 to thereby cause the plunger 42' to extend. This compresses spring 44, forcibly urging the pin outwardly. The pin bears against the lower surface of plate 11 until the selected aperture 60 rotates into alinement with the pin. At that instant, the spring continues to urge the pin outwardly, slamming it into the selected aperture. As the turntable may still be rotating slightly, the shock load thus produced is cushioned by the pivoting or tilting of the pin about its lower swivel joint and also the compression of the resilient material 35. The pivotal or swivel connection and resilient material also accommodates any misalinement or wear of the parts, and insures entry of the pin into the apertures.

When it is desired to withdraw the pin so as to again be able to rotate the turntable, the operator actuates the electric cylinder to contract or withdraw the plunger, which also pulls the pin downwardly due to collar 43 abutting the bumper 66 on the collar 46. The travel of the plunger need only be about 7 two inches.

lclaim:

l. A crane comprising, a nonrotatable member, a turntable member rotatably mounted on said nonrotatable member and having a load carrying support extending therefrom, and a remotely controlled releasable locking means including an axially shiftable pin and a plunger for shifting said pin, said means located on one of said members, a series of apertures in the other of said members for the reception of said pin when alined therewith for locking said members together, said pin being pivotally mounted for slight tilting movement upon locking engagement, and a collar of resilient material around said pin which is compressed by pivotal movement of said pin during locking engagement, a spring acting between said pin and plunger whereby said plunger can act to compress said spring to thereby spring load said pin.

2. The crane set forth in claim 1 further characterized in that said locking means also includes an electric cylinder connected to said plunger for shifting the latter, said pin being pivotally connected to said plunger, whereby said pin can pivot independently of said plunger.

3. ln combination with a crane of the type having a nonlocking the turntable relative to said trolley, said pin being pivotally mounted on said trolley for slight tilting movement upon locking engagement with said turntable, and a collar of resilient material mounted on said trolley and around said pin, said material being compressed by pivotal movement of said pin during locking engagement.

4. The crane set forth in claim 3 further characterized in that said locking means also includes an electric cylinder connected to said plunger for shifting the latter, said pin being pivotally connected to said plunger, whereby said pin can pivot independently of said plunger.

5. The crane of claim 4 including a spring acting between said pin and plunger whereby said cylinder extending cocks said plunger and compresses said spring to thereby spring load said pin.

6. A crane comprising, a nonrotatable member, a turntable member rotatably mounted on said nonrotatable member and having a load carrying support extending therefrom, and a remotely controlled releasable locking means including a shiftable pin and located between said members for releasable locking engagement of said members, said locking means also including a sleeve pivotally mounted adjacent one of its ends to one of said members for pivotal movement relative therefor, said pin being reciprocal in said sleeve for pivotal movement therewith, means on the other of said members for engagement by said pin, a collar of flexible material around the other end of said sleeve and mounted on said one of said member, whereby as said pin and sleeve pivot upon locking engagement of said members, said resilient collar is compressed and cushions the engagement.

7. The crane set forth in claim 6 wherein said locking means also includes a plunger for shifting said pin, and a spring between pin and plunger and tending to be compressed when said plunger is shifting said pin to thereby preload said pin toward a member engaging position. 

